This example demonstrates basic usage of WiFi and Ethernet sniffer mode by saving packets into SD card with pcap format. There is also an option to send pcap file to host via JTAG interface.
This example is based on console component. For more information about console, please refer to [console guide](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/console.html).
To run this example with WiFi interface, you should have one ESP32 dev board integrated with a SD card slot (e.g. [ESP-WROVER-KIT](https://docs.espressif.com/projects/esp-idf/en/latest/hw-reference/modules-and-boards.html#esp-wrover-kit-v4-1)) or just connect [ESP32-DevKitC](https://docs.espressif.com/projects/esp-idf/en/latest/hw-reference/modules-and-boards.html#esp32-devkitc-v4) to a SD card breakout board. To run this example with Ethernet interface option, you should have one ESP32 dev board with physical layer Ethernet support (e.g. [ESP32-Ethernet-Kit](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/hw-reference/esp32/get-started-ethernet-kit.html#)) or connect SPI-Ethernet module (e.g. DM9051) to your dev board.
If you want to send packets to host, make sure to connect ESP32 to some kind of [JTAG adapter](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/jtag-debugging/index.html#jtag-debugging-selecting-jtag-adapter).
-`SD Card` means saving packets (pcap format) into the SD card you plug in. The default SD card work mode is set to SDMMC for target ESP32 and ESP32S3, but SPI is the only choice for other targets.
-`JTAG (App Trace)` means sending packets (pcap format) to host via JTAG interface. This feature depends on [app trace component](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/app_trace.html), Component config -> Application Level Tracing -> Data Destination -> JTAG should be enabled to choose `JTAG (App Trace)` as destination.
- Set the mount point in your filesystem in `SD card mount point in the filesystem` menu item. This configuration only takes effect when you choose to save packets into SD card.
- Set max name length of pcap file in `Max name length of pcap file` menu item.
- Set the length of sniffer work queue in `Length of sniffer work queue` menu item.
- Set the stack size of the sniffer task in `Stack size of sniffer task` menu item.
- For more information related to Ethernet configurations see common configuration of Ethernet from [ethernet examples folder](../../ethernet/README.md#common-configurations).
See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects.
### `pcap` Command Usage When the Destination is `SD Card`
> pcap -f <file> [--open] [--close] [--summary]
> Save and parse pcap file
> -f, --file=<file> name of the file storing the packets in pcap format
> --open open .pcap file
> --close close .pcap file
> --summary option to parse and show the summary of .pcap file
The `pcap` command support some important options as follow:
*`-f`: Specify the name of file which will store the packets or show summary, default value is `sniffer`, and the resulting file name will be like “snifferX.pcap”, here ‘X’ shows the file’s order.
*`--open`: Option to open a '.pcap' file
*`--close`: Option to close the '.pcap' file
*`--summary`: Show the summary of '.pcap' file
### `pcap` Command Usage When the Destination is `Memory`
> pcap -f <file> [--open] [--close] [--summary]
> Save and parse pcap file
> -f, --file=<file> name of the file storing the packets in pcap format
> --open open .pcap file
> --close close .pcap file
> --summary option to parse and show the summary of .pcap file
The `pcap` command support some important options as follow:
*`-f`: Specify the file name to storage packet or show summary
*`--open`: Option to open a '.pcap' file
*`--close`: Option to close the '.pcap' file
*`--summary`: Show the summary of '.pcap' file (needs to be called prior file closing)
### `pcap` Command Usage When the Destination is `JTAG`
pcap command is not used when destination is JTAG. The pcap session is started automatically with the Sniffer start.
## Example Output
### Steps for using **SD Card** to storage packages and watch summary
3. Connect JTAG, run OpenOCD (for more information about how-to please refer to [JTAG Debugging](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/jtag-debugging/index.html)).
4. Telnet to localhost with 4444 port: `telnet localhost 4444`.
5. In the telnet session, run command like `esp32 apptrace start file://sniffer-esp32.pcap 1 -1 20` (more information about this command, please refer to [apptrace command](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/app_trace.html#openocd-application-level-tracing-commands)).
- Make sure you have plugged in your SD card and mount it into filesystem before doing sniffer work or you will get error message like “Create file /sdcard/sniffer0.pcap failed”.
- To protect the SD card, we recommend you to execute command `unmount sd` before you plug out your SD card.
- Make sure to run `esp32 apptrace` command before or immediately after a new sniffer task started when you try this example with JTAG. Otherwise the console will issue warning message `waiting for apptrace established` every 1 second. If the apptrace communication doesn't be established within 10 seconds (can be altered by macro `SNIFFER_APPTRACE_RETRY`), this sniffer command will failed with an error message `waiting for apptrace established timeout`.
(For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you as soon as possible.)